Lihir Volcano | John Seach


New Ireland Province, Papua New Guinea

3.125 S, 152.642 E
summit elevation 700 m
complex volcano

Lihir Island is located north of New Ireland. It consists of several basaltic stratovolcanoes (Luise, Kinami, and Huniho). The youngest volcano, Luise, contains a breached caldera, which forms Luise Harbour. The volcano has an elliptical, breached, steep walled caldera 5.5 long and 3.5 km wide. The caldera floor is covered with scree from the walls.

Lihir is the largest volcano in the chain east of New Ireland. The island contains five coalesced Pliocene-Pleistocene stratovolcanoes. Four young submarine volcanic cones are located offshore from Lihir.

Lihir Island has undergone recent uplift and tilting and is partly fringed by terraced
marine limestone. Observed primary minerals at Lihir include amphibole,
analcite, apatite, biotite, clinopyroxene, hauyne-sodalite, ilmenite, leucite, magnetite, nepheline, olivine, plagioclase, pyrrhotite, chalcopyrite and sanidine.

Gold deposits on Lihir Island
Ladolam hydrothermal system, on Lihir Island contains one of the youngest and largest gold deposits in the world. Deep geothermal brine of magmatic origin
contains 15 parts per billion gold. The current gold flux of 24 kilograms per year means the gold deposit could have formed within 55,000 years. Lihir contains about 1300 tons of gold. Ladolam gold deposit is located at the center of extinct Luise volcano.

Geothermal Activity
Geothermal activity is confined to high and moderate temperature hotsprings in an area of about 15 sq km within the breached Luise Caldera. Activity consists of hot springs, mud pools, and low temperature solfatara. Gas emissions occur along the beach and offshore from Luise Harbour.

Further reading
Kennedy, A.K., Hart, S.R. and Frey, F.A., 1990. Composition and isotopic constraints on the petrogenesis of alkaline arc lavas: Lihir Island, Papua New Guinea. Journal of Geophysical Research: Solid Earth95(B5), pp.6929-6942.

Lihir Volcano Eruptions

The last eruption of Lihir volcano is unknown.